Fan Types: PWM vs. Voltage. The circuit of Figure 2 is essentially an inverting amplifier with high output-current capability. Low speed made the sound worse. Your subscription has been confirmed. Clean Out the Dust. Our expert industry analysis and practical solutions help you make better buying decisions and get more from technology. If your fans are plugged into the computer's motherboard, you might be able to control them using your motherboard BIOS—you can enter the BIOS menu by pressing a key as your computer boots, usually DEL, F2, or something similar. 195 0 obj << /Linearized 1 /O 198 /H [ 2042 525 ] /L 112525 /E 46285 /N 3 /T 108506 >> endobj xref 195 69 0000000016 00000 n 0000001731 00000 n 0000001904 00000 n 0000002567 00000 n 0000003029 00000 n 0000003180 00000 n 0000003346 00000 n 0000003377 00000 n 0000004002 00000 n 0000004165 00000 n 0000004712 00000 n 0000004743 00000 n 0000004774 00000 n 0000005312 00000 n 0000005335 00000 n 0000007216 00000 n 0000007239 00000 n 0000009070 00000 n 0000009101 00000 n 0000009547 00000 n 0000009705 00000 n 0000009728 00000 n 0000011324 00000 n 0000011347 00000 n 0000012805 00000 n 0000012828 00000 n 0000014517 00000 n 0000014540 00000 n 0000016203 00000 n 0000016234 00000 n 0000016719 00000 n 0000016877 00000 n 0000016900 00000 n 0000018709 00000 n 0000018732 00000 n 0000020556 00000 n 0000020792 00000 n 0000020815 00000 n 0000020837 00000 n 0000021311 00000 n 0000021390 00000 n 0000025243 00000 n 0000025732 00000 n 0000025754 00000 n 0000025993 00000 n 0000030269 00000 n 0000030292 00000 n 0000030371 00000 n 0000030921 00000 n 0000031000 00000 n 0000031022 00000 n 0000031393 00000 n 0000031416 00000 n 0000031438 00000 n 0000031778 00000 n 0000034533 00000 n 0000034765 00000 n 0000034999 00000 n 0000035223 00000 n 0000041648 00000 n 0000041671 00000 n 0000041750 00000 n 0000045470 00000 n 0000045493 00000 n 0000045515 00000 n 0000045594 00000 n 0000045728 00000 n 0000002042 00000 n 0000002545 00000 n trailer << /Size 264 /Info 193 0 R /Root 196 0 R /Prev 108495 /ID[<329f6b90d1c4963daf93129b9a1ce18a><7f0ee78d91bc8c7315f62b482d1c7898>] >> startxref 0 %%EOF 196 0 obj << /Type /Catalog /Pages 192 0 R /Metadata 194 0 R /ViewerPreferences << /Direction /L2R >> /StructTreeRoot 197 0 R /MarkInfo << /Marked true >> >> endobj 197 0 obj << /Type /StructTreeRoot /K 45 0 R /ClassMap 50 0 R /ParentTree 187 0 R /ParentTreeNextKey 3 /RoleMap 191 0 R >> endobj 262 0 obj << /S 302 /C 486 /Filter /FlateDecode /Length 263 0 R >> stream Before lowering the PWM, the sound from the fan was a loud "WHEEEEEeeeeeeeee" sound at any speed other than full speed. Whereas in PPM the position of the pulses is proportional to the amplitude of analog modulating signal. Tested using a 12v fan. PWM fans are more power efficient (although I can't imagine them saving you more than a few watts). AC vs DC: The advantages of a DC motor ceiling fan over an AC motor ceiling fan: In most cases, they use less energy – up to 70% less than a standard AC fan. If you can barely hear yourself think over the cacophony of fan noise emanating from your computer, it's probably time to diagnose why your PC sounds like a wind tunnel. Other times, a fan may be on its way to a dusty grave. After lowering the PWM frequency, the noise is … This article will describe how and why this evolution has taken place and will suggest so… In PWM width of the pulses shows proportionality with the amplitude of the message signal.